Angular集成dhtmlx Gantt：按数组属性分组任务的问题

我在Angular项目中使用dhtmlx Gantt，需要实现按值为数组类型的任务属性分组，效果要和官方示例中按owner分组一致。但当前实现存在以下问题：

• 仅数组含单个值的任务能被分组，多值数组的任务没有对应分组
• 未显示默认分组，无分组的任务以树形结构展示

时间线组件分组功能代码 #

setGroupingResources(gantt: any) {
    _.forOwn(this.groupingResources, (data: [], key: String) => {
      gantt.serverList(key, data);
    });
  }

  groupView (gantt: any) {
    gantt.$groupMode = !gantt.$groupMode;
    if (!this.groupByProperty) {
      gantt.groupBy(false);
      return;
    }
    gantt.eachTask((task: any) => {
      if(!task[this.groupByProperty]) task[this.groupByProperty] = 0
      if (task[this.groupByProperty] instanceof Array) {
        var values = task[this.groupByProperty];
        for (var i = 0; i < values.length; i++) {
          task.original_id = task.id;
          gantt.updateTask(task.id)
          var clone = gantt.copy(task);
          clone.original_id = clone.id
          clone.id = gantt.uid();
          clone[this.groupByProperty] = values[i];
          clone.$temporary = true;
          gantt.addTask(clone);
          var clone = gantt.getTask(clone.id);
          clone.parent = clone.$rendered_parent;
        }
      }
    })
    gantt.groupBy({
      groups: gantt.serverList(this.groupByProperty) ,
      relation_property: this.groupByProperty,
      group_id: 'id',
      group_text: 'name',
      delimiter: ", ",
      save_tree_structure: true
    });

  }
ngOnChanges(changes: SimpleChanges) {
    if (!this._gantt) return; 
     this.groupingResources = changes['groupingResources'] && changes['groupingResources'].currentValue || this.groupingResources;
    this.groupByProperty = changes['groupByProperty'] && changes['groupByProperty'].currentValue || this.groupByProperty;
this._gantt.clearAll();
    if (changes['groupingResources']) this.setGroupingResources(this._gantt);
    this.groupView(this._gantt)
    this._gantt.parse({ data: this.data, links: this.links });
    this._gantt.render();
}

示例数据 #

[
  {
    id: 1,
    name: "task #1",
    goal: [1, 2],
  },
  {
    id: 2,
    name: "task #2",
    goal: [1],
  },
  {
    id: 3,
    name: "task #3",
    goal: [],
  },
  {
    id: 4,
    name: "task #4",
    goal: [2],
  },
  {
    id: 5,
    name: "task #5",
    goal: [5, 6],
  },
];

内容的提问来源于stack exchange，提问作者Wafia Mustafa